Travis County Commissioners Court
February 19, 2008
Item 20
Number 20 is to consider and take appropriate action on a final plat for recording in precinct three: the hollow at slaughter creek, section 1 subdivision (140 total lots), and a subdivision construction agreement with centex homes. (Commissioner Daugherty)
>> yes, ma'am?
>> if you will give us your name, we would be happy to get your question, comments, whatever you have.
>> thank you, sir. My name is patricia michael and I’m president of the Texas oaks subdivision, Texas oaks south. And thank you for allowing me to speak, judge Biscoe and members of the Commissioners court. To begin with, I would like to thank Commissioner Daugherty and the county staff who have shown such great patience with our neighborhood process in this building permit. And I would like to get a special thank you to the staff of centex and their engineers for their cooperation with our neighborhood. This talk is asking you to approve the centex plat and I simply wish to make a comment about it because our agreement with centex was that our own water engineer could look at their final water design and comment on it and I would like to have that be a part of the public record. So this talk is a warning, not a criticism. And we are all learning about this together and we all live downstream. Our agreement -- this is a quote from our water engineer's e-mail to us after she looked at the hollow surface water design. And the engineer's name is michelle evans of t.r.c. She looked at these as a member of our neighborhood, she owned a house across the street from me. Based on the information I was given, it appears the drainage calcs were performed according to guidelines. They included a fully developed, the runoff is based on an assumption that the watered is entirely developed, 100 year floodplain along with a critical water quality zone on the plat. Without more information along this stream, high water marks, et cetera, it is difficult to calculate a stream model. The 100 year floodplain showed on the plat is based on what we call a synthetic design storm. As part of the design storm, typically a 24 hour rainfall duration is assumed and a 24 hour rainfall depth is obtained from data that is based on historical rainfall events. The difficulty in modeling an actual storm is estimating where the storm was centered and how much rain fell in exactly what time. Now, our neighborhood was particularly concerned with photos we showed to all concerned including this commission, of water that -- that we photographed at the 100 year storm level on the centex property last year, when there was no such storm on record. Michelle replied, it is possible that the storm event you are referring to may have been less rain than what is considered a one her year event. As far as participation -- as far as precipitation depth. But if it fell during the very short period, it could have been larger than 100 year storm. Foirns, a 24 hour 100 year storm in Travis County is approximately 10 inches. But if the same amount of rain falls in 12 hours, it is considered a 250 year storm. Therefore, this makes it difficult to define a storm based on just depth alone. Without more information the synthetic design storm is considered a reasonably conservative estimate and an accepted standard of practice. It would be nice if all floodplain could be based on real world storm events. Typically there's just not enough historical data, especially on the smaller tributaries. This is a small tributary of slaughter creek. Huge numbers of small lot subdivisions on it. I do wish our science was more of an exact one, but unfortunately it is not. As far as flooding goes, though, I’m of the opinion that it's not a matter of if, but when. Which is why I would recommend that anyone living near the floodplain purchase flood insurance. If the storm that hit marble falls last summer fell on the slaughter creek watershed I would imagine that there would have been many homes flooded or at least close to flooding in our neighborhood and the new neighborhoods.
>> [indiscernible] this information is from aaron j.tulley from a talk he gave to landscape designers at the wild flower center this year. I attended that talk, I am a professional landscaper. He is giving us information for how to disaster proof our future designs. There have been 204 non-partisan scientific studies on climate change. And they all agree with each other. When the co 2 in our atmosphere reaches 450 parts per million, the warming of our atmosphere will be irreversible. That means it will take on its own natural feedback loop and continue warming, no matter what we do. It will simply continue to warm no matter what we do. There are 385 parts per million now and increasing. At our current rate we will reach 204 by 2035. There is a potential of sea level rise of 23 feet. The north pole at the current rate of warming, which has been one degree, will not have ice in 10 years. That does not just affect the coast, it will change the water levels in all of the streams and rivers flowing to the sea. Even slaughter creek. Major storms have increased by 50% in 2006-2007. Major storms are increasing, because of the changes of climate, particularly the viscosity of the ocean and the temperature of the ocean. We looked at a chart of major storms from the 1950's. There was a rise like this. Last year that chart went like this. It was practically unbelievable. 2005 was the hottest year on record, 2007 will probably probably replace that title when all of the numbers are crunched. In 2005 one area of india received 37 inches of rainfall in one day. Now, I’m asking the county to please adjust the topographic heights for construction permits to protect the future occupants from disaster and the government from a huge output in disaster management. The engineering could err on the side of safety, not just legal minimum guidelines. A lot of the land that is left to develop is bottom land that the old timers knew not to build on. At this site the only structures existing are on the highest point of the property. It my also be useful to appropriate out to residents that live no higher than 125 feet both of current map 100 year flood level on a creek to buy federal flood insurance. Right now that land is all zoned as x and people are not required to buy insurance there is a high probability that there will be flooding in many of those areas in the coming years.
>> the map is -- is not the territory and the figures that the engineers are working on are very old, it's a long time to adjust those figures and the climate is changing much faster than that. So I ask you to please take action on it. This is no the a partisan issue. Thank you.
>> we do encourage flood insurance throughout the county. I don't know that we can rir it of the county.
>> -- require it of the county.
>> I believe that is the case. We do advise people when they think that the floodplain is changing. We can't mandate that they buy insurance, but we certainly do make -- make recommendations that -- that, you know, especially if you are outside the floodplain it's -- it's one of the most affordable things that you can do to protect yourself.
>> if we know that you are about to live near a flood prone area, we do all we can to strongly encourage flood insurance.
>> I appreciate that.
>> some do not, but we will have to keep trying to do that. We do appreciate the information. You would like for this to be part of the record.
>> yes, I would. Our county or our subdivision was approved by the county about 20 years ago. None of our houses have ever flooded but this engineer's information is very disturbing to us as well as the water levels that we witnessed last year. And the -- and the -- the subdivisions that have been approved recently by the county along manchaca road and in our area, I have concern for some of the houses in those areas, we have modeled a 10-foot rise on those areas and many of the houses are underwater. Thank you.
>> okay.
>> so the neighborhood association is not opposed -- has not opposed this request. It simply wishes to put us and the applicant on notice.
>> that's correct.
>> thank you, appreciate it.
>> what kind of cost do you think, would you be in the -- in the p.e. At the -- at the table the path that patricia is talking about to do a study that the effect something like this could have, would that be -- would that be an extensive expensive study to determine whether we would really need to go about -- about -- about how we -- look at -- at, you know, engineering projects, I mean, would that be a -- would that be I think that that would be a pretty extensive process?
>> let me be clear about what the question is. I think what you are asking is if we were to take an analysis of the -- of the potential effect of climate change on -- on the -- on the standards that's we use and evaluating hydrologic events and drainage, I think the answer would be it would be an extensive study and -- and potentially very expensive. Possibly inconclusive, there might be quite a bit of -- of a variation of the conclusions about what that effect would be. But -- but with respect to the -- to the synthetic rainstorm event, I just wanted to point out in this area we all rely upon the synthetic storms that are specified in the city of Austin drainage criteria manual. I would think that -- that to actually adopt a new standard for performing studies we would need to look at the science that went into that document. But again any kind of an analysis about the effect of climate change I think would be an extensive and very expensive proposition. Patricia, you see, not that we probably shouldn't think about these things because obviously there is at least -- you know, a school of thought out there that -- that we ought to be doing more than what we are doing? But economics always come into play. It would be interested interesting to see whether if we were to embark on some sort of a -- of a study or process like that how long it would take, how expensive, you know, it -- it would be. You think when we talk about engineering, that the engineering is fairly precise from a science -- science standpoint, except for the fact that it gives -- I guess it depends on, two engineers might derive at a different result or a different answer for something. But -- but only because they might have used different criteria to -- to drive, you know, the process, right? I mean if everybody is saying here's the process that you have to use, this is the only criteria that you can use, you would think that -- I mean if you are given that on a test, somebody is either going to make 100 or somebody is going to make, you know, a 70, unless of course you say well the reason I got my answer is because I used a different set of criteria. And the criteria was driven by -- by number one, what I believe to be the case, I mean, you know, tricia and I talked about this the other day quite a while on the phone. And I -- I want her to know that it's something that I think that we would be interested in. But -- but I also know that -- that the reality of -- of costs in trying to figure out this maybe something that would make a lot of us push back. Is that a reason not to do? It I don't know, I don't want anything thinking we are going to do that because we don't want to do it. There's got to be some reason to go about doing this kind of engineering. You're right god our staff has excellent unbelievable amount of time with this. I know that you all have put as many hours in, you know, as the staff has. Both city and county staff. I appreciate your nice comments thinking about the staff and everybody. I do think that the staff has been really, you know, almost -- almost stretched, you know, with this because we have gone back, gone back, gone back. I’m glad that you all have worked as hard as you have. Anyway had maybe that's the answer to the thing theresa what you mentioned earlier.
>> actually, probably the insurance actuary tables will be what will change all of this. Because we already are seeing the effects of -- of disaster management in this country. There are some countries that have taken very reasonable steps in this direction, australia has already adopted across the board on all of their coastal areas and river areas the requests that I made of setting the -- the lines 25 feet higher. Real estate people have already been trained in the consequences of selling possible flood land. For human occupancy. I think our partisan politics in this country have set us back. I received a degree from dartmouth, university, in sustainable systems design 20 years ago and we studied global warming at that time. The figures that we have seen, the measurements in these last 20 years have been much faster than we ever anticipated that it would happen. And there are a number of people who have very serious concerns about this. I know that -- that probably there is nothing that any one of us in this room can do about the law. I know that the engineers in this room are very concerned about it. We are hearing about it in our professions constantly.
>> we will have an appropriate item on the agenda soon. And invite you to come back and chat with us.
>> thank you.
>> it does seem to me that it's an idea whose time has come. And whether we like it or not, we really need to do more to address it.
>> uh-huh.
>> so why don't we do that. In the meantime I seconded by councilmember the month goes to approve it. Any discussion of the motion? All in favor? Show Commissioners Gomez, Daugherty and yours truly voting -- show a unanimous court. An attentive unanimous court. Thank you all very much.
The Closed Caption log for this Commissioners Court agenda item is provided by Travis County Internet Services. Since this file is derived from the Closed Captions created during live cablecasts, there are occasional spelling and grammatical errors. This Closed Caption log is not an official record the Commissioners Court Meeting and cannot be relied on for official purposes. For official records please contact the County Clerk at (512) 854-4722.
Last Modified:
Wednesday, February 20, 2008 8:09 PM